Method for the treatment of silicates with acids in order to obtain saline solutions free from silica



Jan. 30, W23. 1,443,674

' v G. A BLANC. METHOD FOR THE TREATMENT OF S: LICATES WITH ACIDS iN ORDER TO OBTAIN SALINE SOLUTIONS FREE FROM SILICA. Fl LED OcT. 19, I92! 2 SHEETS'SHEET I (jwmzz, I

Jan. 30, 1923. v 7 1,443,674

. s. A. BLANC; METHOD FOR THE TREATMENT OF SILDCATES w| TH Acl 05 IN ORDER TO OBTAIN SALINE SOLUT ONS FREE FROM SI LIICA FILED OCT. 19, 1921 2 SHEETSSHEET 2 Fly 2.

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Patented Jan. 30, 1%23.

eaten sir err-es career so GIAN ALBERTO BLANC, 0F ROME, ITALY.

METHOD FOR THE TREATMENT OF S ILIOATES WITH ACIDS IN ORDERTO OBTAIN SALINE SOLUTIONS FREE FROM SILICA.

Application filed October 19, 1921. Serial No. 508,808.

To all whom it may concern Be it known that I, GIAN ALBERTO BLANC, a subject of the King of Italy, residing at Rome, in the Kingdom of Italy, have invented certain new and useful Improve-- ments in Methods for the Treatment of Sili cates with Acids in Order to Obtain Saline Solutions Free from Silica, of which the fol lowing is a full, clear, and exact description.

It is .well known that when treating a silicate with an acid in order to solubilize part of its constituents, very great diflicultics are met in attempting to effect the separation of the solution from the residual silica contained in same. Said difliculties arise from the fact that the treatment of silicates with acids causes the formation of colloidal silica, which not only constitutes an impurity of the salts that can be obtained from the solution, but by causing in itsturn the formation of gelspractically prevents filtration.

It is also well known that several methods" have been proposed for the elimination of gelatinous silica from said solutions, but it does not appear that any one of them has given satisfactoryresults on an industrial scale.

of attack is carried out on granulated matc-.

The present invention concerns a method for overcoming the above mentioned difficulty thus enabling to obtain industrially solutions completely free from silica in the treatment ofsilicates with acids.

The method is based on the following two facts which result from practical, experiments: I

1. There are certain silicates, as for instance leucite, with which when the process rial (of the order of about 1 mm. size) the solubilization of the salts that are formed (i. e. of the salts of potassium and aluminium in the aforesaid case of leucite) takes place without the silica (which is liberated in the process) passing into solution in the colloidal state, as long at least, as the mass of the granulated material treated is not me chanically disturbed during the process.

In other words, the acid solution determines the formation of the corresponding soluble salts, Which pass into solution, while.

the totality of the corresponding silica recan 'be avoided in practice) colloidal silica passes into solution, it will be sufficient to cause said solution to circulate through the mass of the residual siliceous material already attacked, in order to free completely the liquid; from any trace of colloidal silica, the latter remaining-occluded in the layer of the insoluble material through which the solution is caused to flow.

Now, according to my invention, in order to secure practically the conditions in which the above mentioned phenomena take place, a layer mustbe formed with the granulated material to betreated, and then the acid solution must be caused to slowly filter through the layer. Thus the acid attacks the silicate forming the corresponding soluble salts, that pass into solution, and leaves the corresponding silica in a state that may be supposed to be like a mass of little crystalline frames of gelatinous silica, which, as'

long as it is not mechanically disturbed reagain onto the filtering layer to be attacked V v in order to eliminate all the residual traces of silica and to complete the extraction of the soluble salts,

This method of circulating the acid solution through the layer of the granulated material during the process of attack prevents any mechanical disturbance of the siliceous filtering layer, which would alter its structure and destroy both its'peculiar properties of being permeable to the saline solution and of retaining occluded the colloidal silica.

In the annexed drawing forming part of this specification twoembodiments of an acids. in which case the liquid is continually brought again process.

The operation proceeds follows: The granulated leuc' preferably as much as possible exempt from fine powder, is introduced into a receptacle 1, Fi l, forming therein layer or i l rness according to the size and c the receptacle, f latter hein 1 with a charging opening 2 and ha'dng a perforated bottom 3. The receptacle is also provided on the side with a for discharging th residu Theiei l "isulojec o. to the x *icentratel ac I to saturation during the potash .he soiution opened ..owed to Iceeds to the alumina concoiloioa iii. mains occim nous 1a;

experience *ientl through eons teriai the solution can be deprived of trace of colloidal silica and passes perfectly clear and pure.

2 shows a modification or the apparatus in which the pipe 5 instead of entering directly the filtering vessel, enters in a saturation tower 10 provided with a--gutter 11, an inlet 12 for the admission of a gaseous acid into the tower 10 and with" an opening 13 for the outiet of the excess gas after the saturation of the liquid which drips from the gutter i1.

.ed at its top esser 4i The apparatus Works in a manner similar to that of the apparatus illustrated in hi l, with the exception that the gaseous acid arriving from the generator is absorbed by the liquid dripping from the gutter 11, and the solution heat serves to keep the liquid at the ebullition temperature.

In this manner one can dissolve by means or a small quantity of liquid, and within a very short time, the totality of the soluble constituent oi? the silicate; further the saline solution, deprived of silica, arriving at high temperature in the basin 8 one can recover separate by a simple cooling process or the materials it contains.

because seoe ac d he tower, r aim ei 1 a ronic in SllOSolml ion or e i, amoane or that has already comoined with the F The Method can Joe applied al o .i soles,

and run in suspenieiy left soluhie recess cccordin" in claim in which .id ion after the passag e through the layer 0 e attacked materi. is again saturated by adding :resh acid it for the object of utilizing aiso the solution or dilution heat. for heatinp the liquid which serves for attacking the mineral.

In testimony whereol I aiiix my signature in the presence of two witnesses.

IAN arenaro BLANG.

Witnesses:

Lnrrnrm Laeoonrrs, /VimrnLM SCHMID. 

